Or a harmonic from, e.g., a television broadband preamp. I have seen
interference from those, although usually at other frequencies, a
number of times. And I concur, this has to be an L1 interference
problem. While it could be within the 20 MHz primary passband, I
strongly suspect broadband rather than carrier noise.

73 gerry

On Wed, Nov 7, 2012 at 10:07 AM, Peter Laws <[log in to unmask]> wrote:
> They don't use the military "P-code", so it's the L1 frequency, 1575.42 MHz
> that is being affected.  Anything +/- 50 MHz or so would be suspect.  Could
> be a spur from an IF on something using a higher frequency, too.
>
>
> On 11/07/12 09:50, Zac Flamig wrote:
>>
>> Just in case any of you guys know something...
>>
>> Zac
>>
>>
>> -------- Original Message --------
>> Subject:        Fwd: GPS Interference
>> Date:   Wed, 07 Nov 2012 05:33:35 -0600
>> From:   Bob Staples <[log in to unmask]>
>> To:     [log in to unmask]
>>
>>
>>
>> Please note the email from Forest Mitchell ( WFO) and advice me of anyone
>> you know or that may be conducting experiments that would interfere with
>> the GPS signal ?
>>
>> Thanks,
>> Bob D Staples
>>
>>
>> -------- Original Message --------
>> Subject:        GPS Interference
>> Date:   Wed, 07 Nov 2012 04:20:17 -0600
>> From:   Forrest Mitchell <[log in to unmask]>
>> To:     Bob Staples <[log in to unmask]>
>> CC:     David Andra <[log in to unmask]>, [log in to unmask],
>> [log in to unmask], John Pike <[log in to unmask]>, Daryl Williams
>> <[log in to unmask]>, Doug Speheger <[log in to unmask]>, Rick
>> Smith <[log in to unmask]>
>>
>>
>>
>> In the past week, we have been experiencing interference with acquiring
>> a GPS signal for the radiosondes we launch for Upper Air flights. The
>> GPS signal is critical towards acquiring accurate wind data aloft.
>>
>> The interference is centered around the NWC, as measured by coworkers
>> using a variety of GPS devices. The interference occurs during the
>> afternoons, affecting us
>> during our launch window from 5-6:30 pm.  It then disappears around 7
>> pm. There is no interference during the morning flights.
>>
>> Is there some experiment being performed by someone within the NWS
>> community that could be causing the interference? We would appreciate
>> your efforts to find the source
>> so that we may create a solution to allow us to perform our mission in
>> its entirety. Thank you.
>>
>>
>>
>>
>>
>>
>>
>
>
> --
> Peter Laws / N5UWY
> National Weather Center / Network Operations Center
> University of Oklahoma Information Technology
> [log in to unmask]
> College of Architecture, Regional and City Planning, MRCP '16
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